Harvard-Westlake student Julia Cukier Siegler, 13, was killed in a school-bus-related accident in 2010. Ever since, her mother has been working for changes.

Jody Cukier Siegler reflects at the memorial set up for her daughter, Julia,… (Katie Falkenberg / For The…)

The accident that claimed 13-year-old Julia Cukier Siegler happened fast, and it replays on an infinite loop in her mother's mind.

"Julia was pressing the button, waiting," said Jody Cukier Siegler. "I could see her blond hair dancing between the branches of the eucalyptus tree. The bus driver motioned. I see the blond hair leave the branches. The bus goes through the light, and I hear Julia being hit."

About 7:20 a.m. on Feb. 26, 2010, the Harvard-Westlake Middle School eighth-grader stepped into the crosswalk on Sunset Boulevard at Cliffwood Avenue, against a red light, to catch her eastbound school bus. The side mirror of a passing SUV clipped her, spinning her to the ground. A car driven by a Palisades Charter High School student ran over her. An ambulance took her to Ronald Reagan UCLA Medical Center, where she died.

In the 21/2 years since, Jody Siegler, 54, has worked doggedly in an effort to improve school bus stop safety. Far from sequestering herself in grief, the former film marketing executive immediately dived into a new role as advocate. It is a role that has often proved frustrating.

No individual or entity was reprimanded or cited in the accident — not the school, not the private school bus company, not the bus driver, not either of the two motorists. The Los Angeles Police Department deemed it a horrible, heart-wrenching accident.

"There was no sanction — just for me and my family," Siegler said. At a memorial service at University Synagogue days after the accident, Jody Siegler explained it this way: "God must have blinked."

Julia was an avid dancer and ceramist who loved the color purple. Purple is the color of the giant bows tied around trees at a memorial at Sunset and Cliffwood where friends have left flowers, teddy bears and purple-painted stones adorned with hearts and written memories.

Impelled by unstoppable grief, Siegler has delved into a thicket of school bus safety regulations and laws. She has enlisted elected officials to join her cause. She has pushed for greater oversight by the California Highway Patrol and urged bus and school officials to consider changing procedures.

She has worked with three Harvard-Westlake students who witnessed the accident from the bus and have raised thousands of dollars in Julia's name to cut down the view-obscuring eucalyptus, lengthen the crossing signal and create a bus safety video they plan to show this fall to new Harvard-Westlake students.

She speaks to anyone who will listen about bus stop visibility and overgrown vegetation on Sunset. She has joined the board of Archer School for Girls, a private school on Sunset Boulevard that has embraced the "Slow Down for Julia" campaign.

In her daughter's name, she has donated a collection of vintage Weil of California dinnerware to the American Museum of Ceramic Art in Pomona. She has written poetry.

There has been progress, but not nearly enough to satisfy Siegler, whose energy snack of choice is black licorice. In March, Atlantic Express, the bus operator that contracts with Harvard-Westlake, asked a CHP officer to review 30 of the company's Sunset bus stops, and the CHP said it was working with the bus company. In addition, John Amato, vice president of Harvard-Westlake, said the school would encourage Atlantic Express to consider using a residential circle off the busy boulevard as a drop-off and pickup location. "We're going to take a very close look at that," he said.

Last year, Siegler and her husband, Scott, a veteran entertainment executive, sold their Brentwood house near where their daughter died and moved to Marina del Rey. Scott Siegler, who has grieved more privately, has urged his wife to move on. She can't. "I'm on a mission," she said.

Reminders repeatedly salt the wound. Last May, a few days after Mother's Day, a Harvard-Westlake "Dear Parents" email landed in her in-box. "At this time of year," it opened, "we offer help in planning your child's 2012-13 school transportation." Jeanne Huybrechts, the head of school, called Siegler to apologize. Amato, who lost his son to cancer, described the lapse as a "horrible, unfortunate mistake."

It sometimes seems that Siegler's efforts bring more anguish than satisfaction. She frets that Harvard-Westlake has not taken steps she considers substantive to improve bus safety.

Still, moments of joy mingle with the ceaseless heartache. A young neighbor used his bar mitzvah proceeds to pay for installation of electronic speed signs near the fateful intersection. Last month, Siegler traveled to a charity golf tournament in Pebble Beach to watch one of Julia's friends compete. He wore custom purple-and-black golf shoes, stitched with R.I.P. J.C.S.

Along her thorny path, Siegler has managed to impress many young people who have taken on her passion and are still pushing for changes. Said one, Eli Kogan, 18, of the bus safety campaign: "Jody is the strongest woman I know."